The 377 species of hummingbirds (Family Trochilidae) occur across the Americas and are considered the most colorful group of birds in the world. This status is achieved due to the majority of s... read more
The approximately 398 species of living parrots (macaws, parakeets, cockatoos, etc.) comprise a more or less homogeneous group of birds found mostly in tropical and subtropical regions. No other gr... read more
In the last years of his life, it was a great concern of Mathias Küster (1950–2022) to write down his ideas on the gestalt biology of snakes, even though he no longer saw himself in a position ... read more
An outline for a biology of freedom using songbirds as an example - Concerning the differentiation of the territorial song
The territory defended by songbirds is much more an acoustic ter... read more
Miniatures on the path. Two red algae in freshwater, two swallowtail butterflies, and two amphibians in comparison
Both native freshwater red algae, Batrac/oospermum and Lemanea, have bee... read more
The egg shell structures of reptiles as a picture of the animal's constitution
The articles on bird egg shells in the Tycho de Brahe yearbooks 1996 and 1997 are here supplemented with an ... read more
On the threefoldness of beetles
Beetles are regarded in their systematic relationships as a superorganism. Concerning their evolutionary differentiation, is there any relation between the... read more
The tunicates - aspects of their threefoldness
The concept of threefoldness (sense-nerve system, metabolic system, rhythmic system) is applied to the hermaphroditic tunicates with their c... read more
Cephalopods, snails and bivalves in their organismic relationship
This contribution was first published in 1973 by Thomas Göbel after mutual discussions on the subject. It is reprinted h... read more